Compensator



Oct. 31,v 1933. A. .URFER 1,933,194

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E ffm/www@ Patented Oct. n 31, 1933 UNITED STATES 'PATENTl OFFICE COMPENSATOR Application March 3, 1930. Serial No. 432,924

14 Claims. (Cl. 33 225) This invention relates to magnetic compensators and more particularly to devices for compensating Compasses for semi-circular deviation.

Among the objects of this invention is to provide an eicient compensator adapted to Withstand the rigors incident to commercial usage and to be particularly suited for economical manufacture.

Another object of the invention is`to provide a device of the character described which has provisions for enabling ready and accurate adjustment, and which is also characterized by features of construction which are designed for obtaining permanence of adjustment and dependability.

Other objects and advantages regarding the structure and use thereof will be pointed out hereinafter in the description and illustrated in the drawing which shows the preferred form of 2g the invention.

Fig. I is an elevation of a compass with a compensator attached thereto.

Fig. II shows a detached outside view of the compensator with its security iplate displaced `from its normal position.

Fig. III is a plan of the compensator with parts broken away, and

Fig. IV is a vertical section taken on line 4-4 of Fig. III.

Having reference to the drawing, illustrates a conventional type `of compass supported on legs 1l and having a freely movable compasscard 12 which is pivoted upon a post 13. The compass illustrated is of the fluid type and the compass-card 12 is immersed in liquid which is enclosed by a cylindrical glass 14. As is usual a lubbers line 15 is provided. While I have cho sen to illustrate a well-known type of compass it is desired that it be understood that the com` pensator of my invention may be associated with any type of a compass which is dependent upon magnetic influence to-indicate direction. It has been used extensively with Compasses of thev magnetic needle type and of the earth inductor type and has utility in any eld where it is desired to eliminate the undesired effects of mag-V of a cup having its lower side closed and its upper side open. The housing may be cast with its various bosses 17, 18, 19, 20, 21 and 22 as integral parts thereof. v r

When the compensator housing is to be at-` tached to a compass, the latter is provided with a depending hub member 24, which has a shoulder 25 turned thereon for tting and centering the housing in respect to the vertical axis of the compass. The housing is provided with an annular recess 26 which is engaged by the shoulder 25 of hub member 24. It will be appreciated that by using a housing Which has its bottom side closed, similar to the housing just described, the operative elements of the compensator are intinker with the same.

The operative parts of the compensator preferably comprise two consequent pole magnets 27, 28 which are supported at right angles to each other and a plurality of magnetic screens 29, 30, which are mounted respectively upon the magnets 27, 28, and which may .be of any suitable magnetic vmaterial having a high permeability, as for exampie, soft iron,.permalloy or hypernick. Two aligned individual bar `mag-- nets with like poles together could be used; but a consequent pole bar magnet is preferred. The consequent pole 'magnets are arranged at right angles in horizontal planes so that the disturbing magnetic inuence which causes semi-circular deviation of a compass may be compensated by compensation of its component influences. When in use the compensator is mounted in respect to a compass in such relation that one of the magnets, for example, magnet 27, may counteractthe north-south component of the` undesired magneticinuence and the magnet 28 may counteract the east-west component of the undesired magnetic influence. The magnetic screens may take the form of sleeves and, as pointed out above, may be made of any suitable magnetic material such 4as soft iron, permalloy or hypernick. The presence of a magnetic screen of this character about a bar magnet materially influences thecharacter of the magnetic iield of the magnet, for the magnetic screen functions as a shunt by which the normal lines of force of the magnetic` eld are caused to converge and pass through the sleeve. Hence the magnetic effect producible by a bar magnet is greatly reduced by the presence of such a highly permeable magnetic screen and it is apparent that similar results are produced when 70 accessible to anybody who might be inclined to a sleeve of magnetic material is positioned about a consequent pole magnet.

A consequent pole magnet has two like poles at its center and the two fields of force normally existing are substantially equal and opposite. It is clear, therefore, that if the eld of one of Athe fields of a consequent pole magnet is altered,

the resultant eiect of the consequent pole magnet will be directional in that the remaining eld of force which hasbeen unaltered has a greater magnetic influence than the other magnetic eld which has had its lines of force shunted through the magnetic screen. The construction making use of this principle in connection with a compensator has been disclosed and claimed in the copending application Serial No. 171,915 of Morris M. Titterington, led March 2, 1927, which is owned by Pioneer Instrument Company, Incorporated.

For practical purposes it is very convenient to make the magnetic screen in the form of a sleeve which may be mounted upon and slid axially of an associated bar magnet. This construction is simple and economical to manufacture and yet may be easily adjusted and made absolutely dependable. Each consequent pole magnet is inthe form of a bar or rod and I prefer to support the same by engaging its ends in the side wall of the housing 16; For this purpose holes 31 and 32 and holes 33 and 34 are provided in pairs for supporting the bar magnets 28 and 27, respectively. These holes are aligned in pairs at right angles and are so dimensioned as to suitably maintain the magnets in place, as by a force fit. The inner surface of the sleeves is circular and the sleeves would be free to rotate or slide axially upon the magnets unless restrained. l

It is convenient and frequently it is necessary that it be possible to control the position of the sleeves by manipulations of elements from outside of the compensator housing 16. For accomplishing this purpose I provide means comprising a pair of rotatable elements 35, 36 which have provisions at their outer ends whereby they may be manipulated. The outer ends 37 and 38, respectively, are journaled in the housing and have slots 39, 40 which may be engaged by a screw-driver. The inner nd of rotatable member 35 is provided with a worm 41 which engages with peripheral grooves 42 formed on the exterior surface of sleeve 30. The inner end of rotatable element 36 is provided with a pinion 43 which engages peripheral grooves 44 formed on the exterior surface of sleeve 29. The grooves 42 and 44 are preferably made annular for `reasons pointed out hereinafter, although the grooves 42 which are engaged by the worm 41 may be made helical, if desired, Without departing from the scope of the invention which contemplates the provision of a novel compensator for magnetic Compasses, and therefore the particular form of driving mechanism of the permeable shields or sleeve members 29 and 30 may be varied to suit particular conditions. It will be apparent that, in the form shown, as either of the rotatable elements is rotated the particular sleeve associated with the element rotated will be translated axially of its associated magnet.

Y It is at once apparent that the groove engaging members at the inner ends of rotatable ele` l ments 35 and 36 could be either both worms or both pinions similar to those illustrated, but

in such event the rotatable elements would be.

disposed at right angles to each other, or else other intermediate connections would have to be used in order to cause the outer ends or heads 37, 38 of the rotatable elementsA to be accessible in the same radial plane. If like sleeve engaging members were used at the inner ends of rotatable elements similar to either of those illustrated, it would be necessary that the rotatable elements be disposed at right angles to. eachother. The applicant's present construction obviates the disadvantages of such an arrangement and enables the outer ends of the rotatable elements to be accessible in one location. With such a construction the compensator may be used and adjusted when associated with a compass which is mounted on an instrument board as all necessary adjustments may be readily made from the front of the board.

The sleeve engaging members 41 and 43 are maintained in close engagement with the grooves of their respective sleeves 30 and 29 by means of cantilever springs 45, 46. The free end of cantilever spring 45 is bent upwardly and engages an annular recess 47 on rotatable element 35 and its anchored end is permanently secured to boss 17. The screw 48 which anchors spring 45 also anchors spring 46 which has its free end turned downwardly and in engagement with annular recess 49 on rotatable element 36. The fit of the rotatable elements in the wall of the housing 16 is of such a nature as to not restrict the tendency of the springs 45 and 46 to urge the groove engaging elements 41 yand 43 into close engagement with the grooves of their respective sleeves. The vertically extending free ends of the springs 45 and 46 preferably should be so disposed as to maintain the rotatable elements 35, 36 in axially immovable positions with the heads 37 and 38 seated in their shoulder holes. The contacting pressures maintained/by springs 45 and 46 are such as to prevent disturbances of any settings which might be effected by the jars or vibrations to which such an instrument is subjected, particularly when used upon aircraft. p

While the arrangement described is particularly efficacious in maintaining settings of the sleeves in respect to the magnets, I prefer, as pointed out hereinbefore, t'o make the grooves 42 and 44 annular so that any rotation of the sleeves in respect to their controlling members 41, 43 will not cause the sleeves to translate axially of the magnets. The use of the annular grooves is further assurance that the settings ofthe sleevesmay be depended upon as being permanent until subsequently readjusted by authorized manipulation. The V-type of teeth is veryl desirable, since they insure proper mesh without permitting loose motion. It is obvious that the novel features just described are adaptable for use in conjunction with a compensator having but one consequent pole magnet instead of two.

In order to avoid confusion regarding which head 38 or 37 should be manipulated for controlling a particular magnet, itis convenient t appropriately identify the two heads by captions N, S for the head 38 by which the northsouth component of undesired magnetic inuence may be corrected and captions E, W

opposite the head 37 by which the east-west Y in one vertical plane rather than at right angles.

So as not to invite tampering by persons unacquainted with the mechanism, `I provide a plate 51 which is pivoted at 52. A spring washer 53 serves to maintain the plate in contact with the housing of the instrument. In its normal position the plate 51 is vertically disposed, Fig. I, in which position an elevation 53 engages hole 32. In such position the heads 37 and 38 are covered. but these heads aremade accessible byswinging the plate 5l to one side to a position similar tor that illustrated in Fig. II.

The compensator housing 16 may be aixed to a compass by the use of screws which extend upwardly through holes 54, 55, in bosses 21 and 20, respectively, Fig. III.

The construction which l have described embodies the principleof my present invention, and I Wish `it to be understood that alterations and modicationsare intended which come within the scope of the claims appended hereto.

What I claim is:

l. The combination with a housing and a pair of consequent pole magnets'supported at right angles to each other therein, of a pair of sleeves of magnetic material, each oi which is mounted on each of said magnets respectively, and each having peripheral grooves on the surface thereof, a rotatable element having a Worm engaging the grooves of one of said sleeves, another rotatable element having a pinion engaging the Vgrooves of the other of said sleeves, and means maintaining said Worm and pinion in engagement with their respective sleeves.

2. The combination with a housing and a pair of consequent pole magnets supported atright angles to each other therein, of a pair of sleeves of magnetic material, each of which is mounted on each of said magnets respectively, and each having peripheral grooves on the surface thereor, a rotatable element having a worm engaging the grooves of one of said sleeves, another rotatable element having a pinion engaging the grooves of the other of said sleeves, and resilient means maintaining said worm and pinion in meshing engagement with the grooves of their respective sleeves.

3. The combination with a housing and a pair of consequent pole magnets supported at right angles to each other therein, of a pair oi sleeves o magnetic material, each of which is mounted on each of said magnets respectively, and each having peripheral grooves, on the surface thereoi, a rotatable element having a worm engaging the grooves oi one oi said sleeves, another rotatable element having a pinion engaging the grooves of the other of said sleeves, both of said rotatable elements having provisions whereby the elements may be manipulated from outside of the housing, and means maintaining said Worm and pinion in engagement with the grooves oi their respective sleeves.

e. The combination with a housing and a pair of consequent pole magnets supported at right angles to each other therein, of a pair of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each having annular grooves, a rotatable element having a worm engaging the grooves of one of said sleeves, another rotatable element having a pinion engaging the grooves'of the other of said sleeves, andresilient means cooperating with said elements and said worm and pinion each oi said elements being supported by the housing and by the action of said resilient means urging said worm and pinion against the grooves of the respective sleeves.

5. The combination with a housing and a pair of consequent pole magnets supported at right angles to each other'therein, of a pair of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each having grooves, means for sliding said sleeves along the axes of the magnets, said means comprising rotatable elements engaging thev grooves of said sleeves, and means supporting said rst-named means in cooperative relation to said sleeves.

6. The combination with a housing and a pair of consequent pole magnets supported at right angles to each other therein, oi a pair of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each having a plurality of annular grooves exterior thereof, means for sliding said sleeves along the axes of the magnets, said means comprising rotatable elements engaging the grooves ot' said sleeves, and resilient means maintaining `said means in engagement with the grooves of the sleeves.

7. The combination with a housing and a pair of consequent pole magnets supported at right angles to each other therein, of a pair of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each having a plurality of annular grooves exterior thereof, means for sliding said sleeves along the axes of the magnets, said means comprising rotatable shafts substantially parallel to each other and having their outer ends journaled in the; Wall of said housing, the inner ends of said shafts having members engaging the grooves of associated sleeves, and means supporting said inner members in engagement with the grooves of associated sleeves.

8. The combination comprising, ahousing, a

pair of consequent pole magnets rigidly supported at right angles to each other in said housing,

of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each being rotatable and slidable in respect to its associated magnet, and means ior sliding said sleeves along the axes of the magnets, said means comprising elements engaging the exterior of said sleeves.

9. The combination comprising, a housing, a pair of consequent pole magnets rigidly supported at right angles to each other in said housing,

a plurality ci sleeves a plurality of sleeves of magnetic material, each of said sleeves` being mounted on each oi said magnets respectively, and each having a plurality of annular grooves exterior thereof, and means for sliding said sleeves along the axes of the magnets, said means comprising rotatable elements engaging the grooves of said sleeves.

l0. The combination comprising, a housing, a pair of consequent pole magnets rigidly supported at right angles to each other in the wall of the housing, a plurality of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each being rotatable and slidable in respect to its associated magnet, means for sliding said sleeves along the axes of the magnets, said means comprising rotatable shafts substantially parallel to each other and having their outer ends journaled in the wall of said housing, the inner ends of said shafts having members' engaging associated sleeves, and resilient means'urging said ciated sleeves.

11. The combination comprising, a housing, a pair of consequent pole magnets supported at right angles to each other in said housing, a plurality of sleeves of magnetic material, each of said sleeves being mounted on each of said magnets respectively, and each having a plurality of grooves exterior thereof, means for sliding said sleeves along the axes of the magnets, said means comprising rotatable shafts substantially parallel to each other and having their outer ends journaled in the wa11.of said housing and accessible from without said housing, the inner ends'of said shafts having members engaging the grooves of associated sleeves, means maintaining said inner members in engagement with the grooves of associated sleeves, and a displaceable security plate mounted on the exterior of said housing and normally covering the outer ends of said rotatable shafts.

12. The combination comprising, a housing, a consequent pole magnet carried by said housing, an axially movable sleeve of 4magnetic material mounted upon said magnet, said sleeve having grooves thereon, means for moving said sleeve along said magnet, said means comprising a member engaging said grooves and a manipulative element, and means yieldingly urging said member into ,engagement with the grooves of said sleeve.

13. The combination set forth in claim 12 in which the grooves on the sleeve are between successive V-type teeth and the member engaging the grooves have corresponding teeth.

14. The combination comprising, a consequent pole bar magnet, a sleeve slidably mounted on said magnet, said sleeve having grooves thereon formed by successive V-type teeth, means engaging the teeth of said groove and having corresponding grooves engaging the V-type teeth Without permitting axial play between said sleeve and magnet, and means `supporting said magnet and said teeth engaging means in assembled relation.

ADOLF URFER. 

